JP2006111821A - Polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyglycolic acid-based polyester resin composition having an improved crystallization rate.
SOLUTION: Polyacetal resin (b) 0.5 parts by weight or more and less than 100 parts by weight is blended with 100 parts by weight of polyglycolic acid-based polyester resin (a) in which glycolic acid units occupy 70 to 100 mol% of the main chain.
[Selection figure] None

Description

  The present invention relates to a polyglycolic acid-based polyester resin composition having an improved crystallization rate.

  In recent years, polyglycolic acid has been attracting attention as an environmentally low-load plastic having an extremely high density and melting point among aliphatic polyesters, excellent mechanical properties, and spontaneous disintegration (Patent Document 1). The crystallization rate of polyglycolic acid is faster than other aliphatic polyesters such as polylactic acid. In addition to molded products by injection molding, a wide range of uses such as sheets and films are expected in the future, but the crystallization rate is even faster. Materials are also expected to meet the needs of a wide range of customers in the future.

On the other hand, there are few examination examples of the improvement of the crystallization speed of aliphatic polyester, and generally the improvement by an inorganic filler etc. is mainly, and the improvement by a resin composition is hardly seen. In particular, there are almost no known examples for improving the crystallization rate by the resin composition for polyglycolic acid.
JP 10-72529 A

  In view of the actual situation, an object of the present invention is to provide a polyglycolic acid-based polyester resin composition having an improved crystallization rate.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above-mentioned problems can be solved by a specific resin composition, and have completed the present invention.

  That is, in the present invention, polyacetal resin (b) 0.5 parts by weight or more and less than 100 parts by weight is blended with 100 parts by weight of polyglycolic acid-based polyester resin (a) in which glycolic acid units occupy 70 to 100 mol% of the main chain. It is related with the polyester resin composition formed.

  According to the present invention, it is possible to provide a resin composition having a high crystallization rate and improved, and the quality of the polyglycolic acid-based polyester resin can be further improved.

  Hereinafter, the present invention will be described in detail. The production method of the polyglycolic acid-based polyester resin (a) in which the glycolic acid unit used in the present invention occupies 70 to 100 mol% of the main chain includes (i) the opening of glycolide which is a cyclic dimer ester of glycolic acid. Examples include a method by ring polymerization, (ii) a method by polycondensation of glycolic acid and / or its carboxylic acid ester, and the like. The glycolide used in the above (i) can be obtained by a sublimation depolymerization method or a solution phase depolymerization method of a glycolic acid oligomer, and it is particularly preferable to use a high-purity glycolide.

Here, the glycolic acid unit is represented by —O—CH ₂ —CO— and can also be referred to as an oxymethylene carbonyl unit.

  The polyester resin (a) used in the present invention may contain units other than glycolic acid units in a range not exceeding 30 mol%, and in the production method of (i), other components other than glycolide may be used. In the manufacturing method of (ii), you may use components other than glycolic acid and / or its carboxylic acid ester for a part of reaction component.

  Examples of other components mentioned here include dicarboxylic acid components, diol components, oxycarboxylic acid components, cyclic ester components, carbonate ester compound components, and the like. These components may be used alone or in combination of two or more. it can.

  Examples of the dicarboxylic acid component include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, and octadecanedicarboxylic acid. Aliphatic dicarboxylic acids having an unsaturated bond such as aliphatic dicarboxylic acids having a linear or branched alkylene group such as 3,3-dimethylpentanedicarboxylic acid and dimer acid, maleic acid, itaconic acid and citraconic acid , Cycloaliphatic dicarboxylic acid and other alicyclic dicarboxylic acids, phthalic acid, isophthalic acid, terephthalic acid, naphthalene dicarboxylic acid such as 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenoxy Ether dicarboxylic acid, 4,4'-diphenyl Tanji carboxylic acids, aromatic dicarboxylic acids such as 4,4'-diphenyl ketone dicarboxylic acid, and, of these carboxylic esters, acid anhydrides and the like.

  Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, and 2,3-butane. Diol, 1,5-pentanediol, 1,2-pentanediol, 2,4-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol , 1,2-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, diethylene glycol, triethylene glycol, dipropylene glycol and the like Or aliphatic diols having a branched alkylene group, polyethylene glycol, poly B propylene glycol, long-chain aliphatic diols of polytetramethylene glycol, alicyclic diols such as 1,4-cyclohexanedimethanol.

  Specific examples of the oxycarboxylic acid component include lactic acid, 2-methyl lactic acid, 3-hydroxypropionic acid, 3-hydroxy-2, 2-dimethylpropionic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-3-methylbutyric acid, 3-hydroxy-3-methylbutyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxy Examples include caproic acid, 2-hydroxyisocaproic acid, lactone ring-opened products, and carboxylic acid esters thereof.

  Specific examples of the cyclic ester component include lactide, β-propiolactone, β-butyrolactone, pivalolactone, β-methyl-β-propiolactone, β-methyl-δ-valerolactone, δ-valerolactone, and ε-caprolactone. Etc. Specific examples of the carbonate compound include dimethyl carbonate, diethyl carbonate, dibutyl carbonate, diphenyl carbonate, and ethylene carbonate.

  It is also possible to use a small amount of an oxycarboxylic acid having at least three hydroxyl groups and carboxyl groups, such as malic acid, citric acid and tartaric acid, and alkyl esters thereof. It is also possible to use a small amount of trihydric or higher alcohol such as trimethylolpropane and pentaerythritol.

  Furthermore, when an optical isomer exists in the above compound, any of D-form, L-form, and racemate may be used.

  The polymerization of the polyglycolic acid-based polyester resin (a) in which the glycolic acid unit used in the present invention occupies 70 to 100 mol% of the main chain is usually performed in the presence of a catalyst. A catalyst can be used individually or in combination of 2 or more types. The polymerization catalyst is not particularly limited, titanium, zirconium, hafnium, vanadium, manganese, iron, cobalt, nickel, zinc, aluminum, gallium, iridium, germanium, tin, antimony, lithium, sodium, cesium, magnesium, calcium, Compounds containing elements such as barium, lanthanum and samarium, for example, organic acid salts, metal alkoxides, organometallic compounds such as metal complexes (acetylacetonate, etc.), metal oxides, metal hydroxides, carbonates, phosphates , Inorganic metal compounds such as sulfates, nitrates and chlorides, tertiary amines such as triallylamine, triethylamine, tri-n-octylamine and benzyldimethylamine, heteropolyacids such as phosphotungstic acid, phosphomolybdic acid and silicotungstic acid And its al Protic acid such as lithium metal salt, sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, 1-propanesulfonic acid, benzenesulfonic acid, p-chlorobenzenesulfonic acid, m-xylene-4-sulfonic acid or the like Derivatives and the like are exemplified.

  An organic or inorganic phosphorus compound can be used in combination with the metal compound catalyst. Specific examples include phosphoric acid, phosphoric anhydride, polyphosphoric acid, metaphosphoric acid, pyrophosphoric acid, phosphorous acid, hypophosphorous acid, tripolyphosphoric acid and their metal salts, ammonium salts, chlorides, esters. Alkyl, aryl acid phosphates, methylphosphonic acid, ethylphosphonic acid, phenylphosphonic acid, naphthylphosphonic acid, dibutylbutylphosphonate, dibutylhydrogen phosphite, tridecylphosphite, triphenylphosphite, diphenylisodecylphosphite, And trisisodecyl phosphite.

  Further, as disclosed in JP-A-8-34843 and JP-A-11-116666, a method for increasing the molecular weight by solid phase polymerization, JP-A-4-189822, JP-A-4-189823, and JP-A-6-41288. No. 6-298920, No. 7-53700, No. 7-70296, No. 7-90043, a method of increasing the molecular weight with an isocyanate compound such as hexamethylene diisocyanate, A method of increasing the molecular weight with an epoxy compound, an aziridine compound, an oxazoline compound, a polyvalent metal compound, a phosphate ester, a phosphite ester, a polyvalent carboxylic acid, a polyvalent acid anhydride, etc., as in US Pat. No. 5,401,796 It is also possible to perform a dehydration condensation reaction using an organic solvent. It is also possible to carry out a transesterification reaction with other polymers under heating.

  The weight average molecular weight (Mw) of the polyglycolic acid-based polyester resin (a) in which the glycolic acid unit used in the present invention occupies 70 to 100 mol% of the main chain is preferably in the range of 10,000 to 1,000,000, and preferably 20,000 to 500,000. The thing of the range of is especially preferable. The weight average molecular weight (Mw) is a value calculated by using polymethyl methacrylate as a standard, which was determined by a GPC measuring device, as will be described later in Examples.

The polyacetal resin (b) used in the present invention is a polymer compound having an oxymethylene group (—CH ₂ O—) as a main structural unit, and contains other structural units in addition to the polyoxymethylene homopolymer and the oxymethylene group. It may be any of copolymers (including block copolymers) and the like, and the molecule may have a branched or crosslinked structure as well as a linear shape.

  In general, homopolymers are produced by polymerization of anhydrous formaldehyde or polymerization of trioxane, a cyclic trimer of formaldehyde. Usually stabilized against thermal degradation by end caps.

The copolymer generally contains formaldehyde or a cyclic oligomer of formaldehyde represented by the general formula (CH ₂ O) _n (where n is an integer of 3 or more), for example, trioxane, cyclic ether and / or cyclic formal. It is produced by copolymerization and is usually stabilized against thermal decomposition by removing terminal unstable moieties by hydrolysis. In the polyacetal resin (b) used in the present invention, a polyacetal resin copolymer is particularly preferable from the viewpoint of hue stability of resin composition pellets and / or molded articles.

  The trioxane used as the main raw material of the polyacetal resin copolymer is generally obtained by reacting an aqueous formaldehyde solution in the presence of an acidic catalyst, and is used after being purified by a method such as distillation. The trioxane used for the polymerization is preferably one containing as little impurities as possible, such as water, methanol and formic acid.

  Examples of the cyclic ether and / or cyclic formal compound used in the production of the polyacetal resin copolymer include ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, epibromohydrin, styrene oxide, oxetane, and 3,3-bis (chloromethyl). ) Oxetane, tetrahydrofuran, trioxepane, 1,3-dioxolane, ethylene glycol formal, propylene glycol formal, diethylene glycol formal, triethylene glycol formal, 1,4-butanediol formal, 1,5-pentanediol formal, 1,6-hexane Diol formal etc. are mentioned. Among these, one or more selected from the group consisting of ethylene oxide, 1,3-dioxolane, 1,4-butanediol formal, and diethylene glycol formal are preferable, and 1,3-dioxolane is particularly preferable. A particularly preferred copolymer composition of these cyclic ethers and / or cyclic formal compounds is 0.5 to 20% by weight.

  The polyacetal resin copolymer is generally obtained by a method in which an appropriate amount of molecular weight modifier is further added and cationic polymerization is performed using a cationic polymerization catalyst. Examples of molecular weight modifiers include low molecular weight acetal compounds having alkoxy groups such as methylal, methoxymethylal, dimethoxymethylal, trimethoxymethylal, oxymethylene di-n-butyl ether, alcohols such as methanol, ethanol, butanol, esters Examples include compounds, acid compounds, water and the like. Among these, a low molecular weight acetal compound having an alkoxy group is particularly preferable.

  Cationic polymerization catalysts used for the production of the polyacetal resin copolymer include lead tetrachloride, tin tetrachloride, titanium tetrachloride, aluminum trichloride, zinc chloride, vanadium trichloride, antimony trichloride, phosphorus pentafluoride, pentafluoride. Trifluoride such as antimony, boron trifluoride, boron trifluoride diethyl etherate, boron trifluoride dibutyl etherate, boron trifluoride dioxanate, boron trifluoride acetate anhydrate, boron trifluoride triethylamine complex Boron halide coordination compounds, perchloric acid, acetyl perchlorate, t-butyl perchlorate, hydroxyacetic acid, trichloroacetic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid and other inorganic and organic acids, triethyloxonium Tetrafluoroborate, Li phenylmethyl hexafluoroantimonate, allyl diazonium hexafluorophosphate, complex salt compounds such as allyl diazonium tetrafluoroborate, diethyl zinc, triethyl aluminum, alkali metal salts such as diethyl aluminum chloride, heteropoly acid and isopoly acid. Among these, three compounds such as boron trifluoride, boron trifluoride diethyl etherate, boron trifluoride dibutyl etherate, boron trifluoride dioxanate, boron trifluoride acetate anhydrate, boron trifluoride triethylamine complex compound, etc. Boron fluoride coordination compounds are preferred. These catalysts may be used after diluting with an organic solvent or the like.

  In the production of the polyacetal resin copolymer, the polymerization apparatus is not particularly limited, and a known apparatus is used, and in particular, a continuous polymerization apparatus with a biaxial paddle or the like is preferably used. The polymerization temperature is preferably maintained at 65 to 135 ° C. The deactivation after the polymerization is carried out by adding a basic compound or an aqueous solution thereof to the product reaction product discharged from the polymerization machine after the polymerization reaction or the reaction product in the polymerization machine. Basic compounds for neutralizing and deactivating the polymerization catalyst include ammonia, amines such as triethylamine, tributylamine, triethanolamine, and tributanolamine, or hydroxylation of alkali metals and alkaline earth metals. Materials, salts, and other known catalyst deactivators are used. Moreover, it is preferable to add these aqueous solutions to a product rapidly after a polymerization reaction, and to make it deactivate. After the polymerization method and the deactivation method, washing, separation and recovery of unreacted monomers, drying, and the like are further performed by a conventionally known method as necessary.

  The polyacetal resin (b) of the present invention preferably has a melt index in the range of 0.01 to 500 g / 10 min, particularly preferably in the range of 0.1 to 100 g / 10 min.

  In the present invention, a resin composition is prepared using the polyglycolic acid-based polyester resin (a) in which the glycolic acid unit occupies 70 to 100 mol% of the main chain and the polyacetal resin (b). The composition ratio of (a) and (b) requires that the polyacetal resin (b) is 0.5 parts by weight or more and less than 100 parts by weight with respect to 100 parts by weight of the polyester resin (a). In particular, the polyacetal resin (b) is preferably 1 to 50 parts by weight. When the amount of the polyacetal resin (b) is less than 0.5 parts by weight relative to 100 parts by weight of the polyester resin (a), the improvement of the crystallization rate is small.

  Although there is no restriction | limiting in particular as a composition preparation method of this invention, It prepares by melt-kneading the polyester resin (a) and a polyacetal resin (b) component fundamentally. It is desirable that the processing conditions are kneading at a temperature of not less than the melting points of (a) and (b), preferably 210 ° C. or more and 250 ° C. or less for at least 30 seconds. The specific embodiment of the preparation method is not particularly limited, and can be generally prepared by a known equipment and method as a preparation method of the synthetic resin composition. That is, a general method is to mix necessary components and knead them using a single or twin screw extruder or other melt kneading apparatus. In addition, in order to improve the dispersion and mixing of each component, a part or all of the resin component is finely pulverized, mixed and melt-extruded, and then a method for forming the pellets, or a part of the components constituting the composition is previously obtained. It is also possible to use a method of melting and kneading (master batch) and further kneading this with the remaining other components to obtain a composition of a predetermined component or a molded product.

  The resin composition of the present invention can further contain various known stabilizers. In particular, blending an antioxidant is particularly preferable from the viewpoint of the stability of the hue of the resin composition pellets and / or the molded product. Examples of the antioxidant used in the composition of the present invention include phenolic (such as hindered phenols), amine (such as hindered amines), phosphorus, sulfur, hydroquinone, and quinoline antioxidants. Can be mentioned.

  Phenol antioxidants include hindered phenols such as 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 4,4′-methylenebis (2,6-di-tert-butylphenol). 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 2,6-di-tert-butyl-p-cresol, 1,3,5-trimethyl-2,4,6-tris (3 , 5-di-t-butyl-4-hydroxybenzyl) benzene, 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], pentaerythritol tetrakis [ 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl-5-methyl) 4-hydroxyphenyl) propionate], n-octadecyl-3- (4 ′, 5′-di-t-butylphenol) propionate, n-octadecyl-3- (4′-hydroxy-3 ′, 5′-di-t -Butylphenol) propionate, stearyl-2- (3,5-di-t-butyl-4-hydroxyphenol) propionate, distearyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate, 2-t- Butyl-6- (3-tert-butyl-5-methyl-2-hydroxybenzyl) -4-methylphenyl acrylate, N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-) Hydrocinnamamide), 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyl Xyl] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane, 4,4′-thiobis (3-methyl-6-tert-butylphenol), 1,1 , 3-tris (2-methyl-4-hydroxy-5-t-butylphenol) butane.

  Amine-based antioxidants include hindered amines such as tri- or tetra-C1-3 alkylpiperidine or derivatives thereof [for example, 4-methoxy-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2, 2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, etc.], bis (tri, tetra or penta C1-3 alkylpiperidine) C2-20 alkylene dicarboxylate [for example Bis (2,2,6,6-tetramethyl-4-piperidyl) ogisalate, bis (2,2,6,6-tetramethyl-4-piperidyl) malonate, bis (2,2,6,6-tetra Methyl-4-piperidyl) adipate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6) , 6-Pentamethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) terephthalate], 1,2-bis (2,2,6,6-tetramethyl-4- Piperidyloxy) ethane, phenyl-1-naphthylamine, phenyl-2-naphthylamine, N, N′-diphenyl-1,4-phenylenediamine, N-phenyl-N′-cyclohexyl-1,4-phenylenediamine and the like. .

  Examples of phosphorus antioxidants include triisodecyl phosphite, trisnonyl phenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl). Octyl phosphite, 4,4′-butylidenebis (3-methyl-6-tert-butylphenyl) ditridecyl phosphite, tris (branched C 3-6 alkylphenyl) phosphite [eg, tris (2,4-di-t -Butylphenyl) phosphite, Tris (2-t-butyl-4-methylphenyl) phosphite, Tris (2,4-di-t-amylphenyl) phosphite, Tris (2-t-butylphenyl) phosphite Tris [2- (1,1-dimethylpropyl) -phenyl] phosphite, tris [2,4- (1,1-dimethylpropyl) -phenyl] phosphite etc.], bis (2-tert-butylphenyl) phenyl phosphite, tris (2-cyclohexylphenyl) phosphite, tris (2-t- Butyl-4-phenylphenyl) phosphite, bis (C3-9 alkylaryl) pentaerythritol diphosphite [e.g., bis (2,4-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, etc.], triphenyl phosphate Stabilizers (eg 4-phenoxy-9-α- ( -Hydroxyphenyl) -p-cumenyloxy-3,5,8,10-tetraoxa-4,9-diphosphapyro [5,5] undecane, tris (2,4-di-t-butylphenyl) phosphate, etc.), diphosphonites Stabilizers (for example, tetrakis (2,4-di-t-butyl) -4,4′-biphenylenediphosphonite) are included.

  Examples of the hydroquinone antioxidant include 2,5-di-t-butylhydroquinone. Examples of the quinoline antioxidant include 6-ethoxy-2,2,4-trimethyl-1 , 2-dihydroquinoline and the like, and examples of the sulfur-based antioxidant include dilauryl thiodipropionate and distearyl thiodipropionate.

  These antioxidants can be used alone or in combination of two or more. The content of the antioxidant is, for example, selected from the range of 0.01 to 5 parts by weight, preferably 0.05 to 2.5 parts by weight, particularly about 0.1 to 1 part by weight with respect to 100 parts by weight of the polyester resin (a). it can.

  In addition, as the heat resistance stabilizer used in the resin composition of the present invention, as a weather resistance (light) stabilizer such as metal hydroxides and inorganic salts, metal salts of fatty acids, nitrogen-containing compounds such as amidine compounds and amide compounds, etc. In general, benzotriazole materials, benzophenone materials, aromatic benzoate materials, hindered amine materials (piperidine derivatives having a sterically hindered group) and the like are generally used.

  Furthermore, various known additives can be blended in the composition of the present invention in order to improve its physical properties according to the intended use. Examples of additives include various colorants, lubricants, mold release agents, nucleating agents, surfactants, heterogeneous polymers, organic polymer modifiers, inorganic, organic, metallic, etc. fibrous, granular, plate-like These fillers can be used, and one or more of these can be used in combination.

  Further, the above-mentioned stabilizers, additives and the like can be added at any stage, for example, once added to the polyester resin (a), once added to the polyacetal resin (b), or added during the preparation of the resin composition. It is also possible to add and mix immediately before obtaining the final molded product.

  The polyglycolic acid-based polyester resin composition of the present invention obtained as described above has a high crystallization rate and can be further improved in quality.

  In particular, the polyester resin composition preferably has a temperature difference (Tm−Tc) of 35 ° C. or less between its melting point (Tm) and crystallization temperature (Tc). Here, Tm and Tc are melting points and crystallization temperatures measured by DSC (differential scanning calorimetry), as will be described later in Examples, and the smaller the (Tm−Tc), the faster the crystallization rate of the resin composition. It is shown that.

  In addition, the resin composition of this invention can respond to conventionally well-known molding methods, such as an injection molding method, an extrusion molding method, a blow molding method, a sheet molding method, a film molding method, and a fiber molding method.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
Production Example 1 Preparation of Polyglycolic Acid Resin (a-1) Under a nitrogen atmosphere, 100 parts by weight of glycolide and SnCl ₄ · 6.5H ₂ O as a catalyst were charged in a batch-type stirrer at a temperature of 175 ° C. The polycondensation reaction was carried out by stirring for 2 hours. The reaction product was discharged, cooled in a water bath, cut with a cutter to form a pellet, and further dried under reduced pressure at 150 ° C. to obtain a polyglycolic acid resin (a-1). The weight average molecular weight of the obtained polymer was 55,000. The weight average molecular weight was measured by the following method.
[Weight average molecular weight]
Measurement was performed at 40 ° C. by using a GPC measuring apparatus and using HFIP (hexafluoroisopropanol) / 10 mM sodium trifluoroacetate as an eluent. Polymethyl methacrylate was used as a standard sample.
Production Example 2 Preparation of High Molecular Weight Polyglycolic Acid Resin (a-2) The polymer obtained in Production Example 1 was subjected to solid phase polymerization at 210 ° C. under a reduced pressure of 0.1 mbar for 25 hours to obtain a high molecular weight polyglycolic acid. Resin (a-2) was obtained. The obtained polymer had a weight average molecular weight of 14,000.
Production Example 3 Polymerization of Polyacetal Resin Copolymer (b-1) Continuously constituted by a barrel having a shape in which two circles partially overlap each other with a jacket through which a heat (cooling) medium passes and a rotating shaft with a paddle Using a mixed mixing reactor, while rotating two rotating shafts with paddles at 150 rpm each, trioxane 100 parts by weight, 1,3-dioxolane 3.2 parts by weight, and methylal 0.1% by weight as a molecular weight regulator Part was continuously added at a predetermined ratio, and boron trifluoride as a catalyst was continuously added and supplied to perform bulk polymerization. While rapidly passing the reaction product discharged from the polymerization machine through a crusher, the reaction product was added to a 60 ° C. aqueous solution containing 0.05% by weight of triethylamine to deactivate the catalyst. Furthermore, after separation, washing and drying, a crude polyacetal resin was obtained.

Next, 3 parts by weight of a 5% by weight aqueous solution of triethylamine and 100 parts by weight of this crude polyacetal resin, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) as a stabilizer 0.3 parts by weight of propionate] was added and melt-kneaded at 210 ° C. with a twin-screw extruder to remove unstable parts to obtain a pellet-like polyacetal resin copolymer (b-1). The melt index of the obtained polymer was 9.5 g / 10 min. The copolymer composition was confirmed to be 3.4% by weight by proton NMR measurement using hexafluoroisopropanol d2 as a solvent.
Production Example 4 Polymerization of Polyacetal Resin Homopolymer (b-2) Using the same continuous mixing reactor as in Production Example 3, while rotating two rotating shafts with paddles at 150 rpm, 100 parts by weight of trioxane, Further, 0.1 parts by weight of methylal as a molecular weight regulator was continuously added at a predetermined ratio, and boron trifluoride as a catalyst was continuously added and supplied to perform bulk polymerization. While rapidly passing the reaction product discharged from the polymerization machine through a crusher, the reaction product was added to a 60 ° C. aqueous solution containing 0.05% by weight of triethylamine to deactivate the catalyst. Furthermore, after separation, washing and drying, a crude polyacetal resin was obtained.

Next, the crude polyacetal and acetic anhydride were reacted at a temperature of 145 ° C. for 1 hour using cyclohexane as a solvent and sodium acetate as a catalyst to stabilize the ends. Subsequently, 0.3 parts by weight of pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] as a stabilizer is added to 100 parts by weight of the obtained polyacetal resin. The mixture was melt-kneaded at 210 ° C. with a twin-screw extruder to obtain a pellet-like polyacetal resin homopolymer (b-2). The melt index of the obtained polymer was 12.2 g / 10 min.
Examples 1-4, Comparative Examples 1-3
As shown in Table 1, after the polyester resin (a-1, a-2) and the polyacetal resin (b-1, b-2) were mixed in advance, the resin temperature was 225 ° C. using a twin screw extruder. A melt-kneading treatment was performed to prepare a pellet-like composition, and then an ISO test piece was molded with an injection molding machine to evaluate the crystallization speed. The results are shown in Table 1. For comparison, the same evaluation was performed when only the polyester resin (a-1) was used. The results are also shown in Table 1.
The crystallization rate was evaluated by the following method.
[Evaluation of crystallization rate]
Samples of 10 mg each were cut out from the ISO tensile test pieces, and Tm [peak temperature of melting point] (° C.) at DSC (differential scanning calorimetry) at a heating rate of 10 ° C./min and a cooling rate of −10 ° C./min Tc [peak temperature of crystallization temperature] (° C.) was measured, and Tm−Tc (° C.) was calculated. still. When a plurality of Tm and Tc existed, the value on the high temperature side was used. The higher the Tc and the smaller the Tm-Tc, the faster the crystallization rate.
Example 5
As shown in Table 1, Production Example 3 except that the polyester resin (a-1) and pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] were not added. The polyacetal resin (b-1 ′) prepared in the same manner as above was mixed in advance, and then melt-kneaded at a resin temperature of 225 ° C. using a twin-screw extruder to prepare a pellet-like composition, followed by injection An ISO test piece was molded with a molding machine, and the crystallization rate was evaluated. The results are shown in Table 1.

Claims (6)

Polyester resin composition obtained by blending 0.5 parts by weight or more and less than 100 parts by weight of polyacetal resin (b) to 100 parts by weight of polyglycolic acid-based polyester resin (a) in which glycolic acid units occupy 70 to 100 mol% of the main chain object. The polyacetal resin (b) is obtained by copolymerizing formaldehyde or a cyclic oligomer of formaldehyde represented by the general formula (CH ₂ O) _n (where n is an integer of 3 or more) with cyclic ether and / or cyclic formal. The polyester resin composition according to claim 1, which is a produced polyacetal resin copolymer. The polyester resin composition according to claim 2, wherein the polyacetal resin (b) is a polyacetal resin copolymer obtained by copolymerizing a cyclic ether and / or a cyclic formal compound in a proportion of 0.5 to 20% by weight. The polyester resin composition according to claim 2 or 3, wherein the polyacetal resin (b) is a polyacetal resin copolymer obtained by copolymerizing trioxane, which is a cyclic oligomer of formaldehyde, and 1,3-dioxolane, which is cyclic formal. Further, at least one antioxidant selected from phenolic antioxidants, amine antioxidants, phosphorus antioxidants, sulfur antioxidants, hydroquinone antioxidants, quinoline antioxidants, and polyesters The polyester resin composition according to any one of claims 1 to 4, comprising 0.01 to 5 parts by weight based on 100 parts by weight of the resin (a). The polyester resin composition according to any one of claims 1 to 5, wherein the temperature difference between the melting point of the polyester resin composition and the crystallization temperature is 35 ° C or less.